Image processing equipment has utility in a wide range of industries. Color-proofing is the procedure used by the printing industry for creating representative images that replicate the appearance of printed images without the cost and time required to actually set up a high-speed, high-volume printing press to print an example of the images intended. One such color proofer is a lathe bed scanner that utilizes a thermal printer having half-tone capabilities. This printer is arranged to form an image on a thermal print medium in which a dye donor material transfers a dye to the thermal print medium upon a sufficient amount of thermal energy. This printer includes a plurality of diode lasers that can be individually modulated to supply energy to selected areas of the medium in accordance with an information signal. The print-head of the printer includes one end of a fiber optic array having a plurality of optical fibers coupled to the diode lasers. The thermal print medium and dye donor material are supported on a rotatable imaging drum, and the print-head with the fiber optic array is movable relative to the longitudinal axis of the drum. The dye is transferred to the thermal print medium as the radiation, transferred from the diode lasers to the dye donor material by the optical fibers, is converted to thermal energy in the dye donor material or media.
The generally abrasive dye donor media is stored in rolls and is transported in the form of a web to the print head via conventional web transport elements. Presently, four different rolls of dye donor media are used, and each roll includes a different dye donor material from among black, yellow, magenta and cyan. These rolls of dye donor media are ultimately cut into dye donor sheets and then transported to the vacuum imaging drum for forming the medium from which dyes imbedded therein are transported to the thermal print media resting thereon. In order to transport the dye donor media, the imaging processing equipment typically includes some sort of web or media transport means operably connected to each roll of dye donor material. Most existing media transport means includes a plurality of closely spaced transport rollers made generally of either steel or plastic. These roller materials, when exposed to corrosive environments existing in image processing equipment, are subject to wear and abrasion that affects the reliability of the imaging process.
One problem associated with current media transport means is that any of the rolls of generally abrasive dye donor media can potentially slip as it is being transferred to the imaging drum. This, of course, could cause misalignment and poor registrability of the image formed on the media and thus loss of expensive media material. Another problem associated with the present media transport means is that the rollers are generally not as durable with continuous exposure to a corrosive environment.
Therefore, a need persists for image processing equipment in which the generally abrasive dye donor media is conveyed during processing to the vacuum image drum by a wear and abrasive resistant means which is reliable, economical and easy to develop, to install and operate.